Physicists detect geo-neutrinos from deep within Earth’s core

Washington, March 27 (ANI): In a new study, two University of Massachusetts Amherst physicists are measuring some of the faintest and rarest particles ever detected, geo-neutrinos, from deep within Earth, with the greatest precision yet achieved.

The data, being collected using a delicate instrument located under a mountain in central Italy, reveal, for the first time, a well defined signal, above background noise, of the extremely rare geo-neutrino particle from deep within Earth.

Geo-neutrinos are anti-neutrinos produced in the radioactive decays of uranium, thorium, potassium and rubidium found in ancient rocks deep within our planet.

These decays are believed to contribute a significant but unknown fraction of the heat generated inside Earth, where this heat influences volcanic activity and tectonic plate movements, for example.

Borexino, the large neutrino detector, serves as a window to look deep into the Earth’s core and report on the planet’s structure.

Borexino is located at the Laboratorio Nazionale del Gran Sasso underground physics laboratory in a 10 km-long tunnel about 5,000 feet (1.5 km) under Gran Sasso, or Great Rock Mountain, in the Appenines and operated by Italy’s Institute of Nuclear Physics.

The instrument detects anti-neutrinos and other subatomic particles that interact in its special liquid center, a 300-ton sphere of scintillator fluid surrounded by a thin, 27.8-foot diameter transparent nylon balloon.

The new Borexino data have stronger significance because of their purity and the absence of nuclear reactors.

According to UMass Amherst researcher Andrea Pocar, “The Borexino detector is very clean and has lower levels of radioactive impurities than ever achieved in experiments of this kind.”

“It is indeed a very ‘quiet’ apparatus for the observation of low energy neutrinos, and exceptionally precise for distinguishing these particles by origin, either solar, geo or human-made,” he said.

The small number of anti-neutrinos detected at Borexino, only a couple each month, helps to settle a long-standing question among geophysicists and geologists about whether our planet harbors a huge, natural nuclear reactor at its core.

Based on the unprecedently clear geo anti-neutrino data, the answer is no, say the UMass Amherst physicists.

“This is all new information we are receiving from inside the Earth from the geo-neutrino probe,” explained UMass Amherst researchers Laura Cadonati.

“Our data are exciting because they open a new frontier. This is the beginning. More work is needed for a detailed understanding of Earth’s interior and the source of its heat, with new geo-neutrino detectors above continental and oceanic crust,” she said. (ANI)

Laser cooling may be used to create “exotic” states of matter

Washington, September 9 (ANI): In a new study, scientists have determined that the technique of laser cooling could be used to create “exotic” states of matter.

According to a report in National Geographic News, in a new technique, Martin Weitz and Ulrich Vogl of the University of Bonn in Germany used a laser to bring the temperature of dense rubidium gas far below the normal point at which the gas becomes a solid.

Previous research had been able to use lasers to quickly “supercool” only very diluted gases.

But, “here’s a case where you shine a laser on something and it actually cools down, and not just a handful of atoms, but a macroscopic object,” said Trey Porto, a physicist with the National Institute of Standards and Technology’s laser-cooling group.

The process could be used to create fascinating new states of matter, according to the study authors.

“For example, if you can very quickly cool water much lower than zero Celsius (32 degrees Fahrenheit), where it would normally turn to ice, exotic crystalline and glassy states of matter would be predicted,” Weitz said.

The new technique could also be used in cooling mechanisms to boost the efficiency of some stargazing equipment, he added.

“If you could cool thermal cameras that look at the stars, they may have less noise and be more sensitive,” he said.

Since a laser’s color is linked to its intensity, the new technique is based on using a red laser in which the frequency has been adjusted so that the beam affects the atoms only when they collide with each other.

Weitz and Vogl shone this laser beam into gaseous rubidium atoms in a high-pressure “atmosphere” of argon.

In the experiment, the rubidium gas fell from 662 degrees Fahrenheit (350 degrees Celsius) to almost 536 degrees Fahrenheit (280 degrees Celsius) within mere seconds.

Much more research needs to be done before the laser-cooling process can be used in real-world applications, study co-author Weitz cautioned.

But, NIST’s Porto said the work already represents a major departure from traditional cooling of diluted gases, which are currently used for studying quantum effects or preparing gas samples for atomic clocks.

“I think the really amazing thing is that you can even get cooling in this regime, because it’s a really dense gas and a very different mechanism,” Porto said.

“Traditional cooling powers are so tiny. To cool a physical object by a measurable degree with a laser is amazing,” he added. (ANI)